Like the L 76, the L 77v had a fabric-covered welded-steel fuselage and wooden dual-spar wings with plywood skins supported by N-type struts. It was armed with twin 7.92 mm (.312 in) machine guns in fixed forward-firing positions and a third on a ring mounting in the rear cockpit.

Three of the aircraft saw service performing armament trials in Lipetsk in the Soviet Union; these included one aircraft testing a free-mounted 20 mm cannon. The fourth aircraft had been destroyed while undergoing tests in March 1929. Between December 1929 and their retirement in October 1931, the surviving L 77vs were based at the StaakenErprobungsstelle (Test Centre).